Keyless device of vehicle

A keyless device for a vehicle, comprising:

• an on-vehicle device and a portable device, the on-vehicle device having a plurality of search signal transmitting means that each transmits a search signal to an interior and an exterior of the vehicle to search for the portable device, and with an answer signal receiving means that receives an answer signal from the portable device in reply to the search signal,
• the portable device having a search signal receiving means for receiving the search signal and an answer signal transmitting means for transmitting the answer signal based on the search signal;
• a position detecting means for detecting based on the answer signal that the portable device is within a search area where the search signal transmitting means searches for the portable device;
• and
• a search area setting means for setting search areas in such a way that a first search area of a first search signal transmitting means and a second search area of a second search signal transmitting means differ from each other and differ in area size, and an overlapped area of the first and second search areas corresponds only to the interior of the vehicle,
• wherein the answer signal transmitting means transmits the answer signal in a case where a receiving intensity of the search signal received by the search signal receiving means is larger than a threshold value,
• the search area setting means changes threshold values to set the first search area and the second search area, and
• during a time that both the first search signal transmitting means and the second search signal transmitting means are transmitting the search signals, the search signal transmitted by the first search signal transmitting means searches the left side of the vehicle while the search signal transmitted by the second search signal transmitting means searches the right side of the vehicle.